Variable stroke pump



Oct. 28, 1952 G. P. E. HOWARD 2,615,398

VARIABLE STROKEPUMPY Filed June 18, 1948 4 Sheets-Sheet l v .R v)

lnvenf'o Q 611:: Pm IP Euor gamma Attorney Oct. 28,1952 G, HOWARD 2,615,398 7 VARIABLE STROKE PUMP Filed June 18, 1948 4 Sheets-Sheet 2 4 I III i 145: PHIL/P 533152535 MA 9,; Ha,

Oct. 28, 1952 HOWARD 2,615,398

VARIABLE STROKE PUMP Filed June 18, 1948 4 SheetSTSheet 5 I l... l5 E 5 27 l 8 32 kg 9 w E Inventor cues PHIL/P5107 flow m0 mmu Attorney Oct. 28; 1952 I G. P. E. HOWARD VARIABLE STROKE PUMP 4 Sheets-Sheet 4 Filed June 18, 1948 W WW R r nw flm 9 mH rv fl w E m Patented Get. 28, 1952 om-ED STATES f VARIABLE s'rnoxia Y PUMP. Giles PhilipEliot How rd, Lriton, England Application'June 18, 1948, Serial No.:33;'712

In Great Britain May 1-, 1947 .4 Claims. (01, its-"23 j 'l his invention relates to variablestroke pumps such as are employed in adding chemicals, in .variable amounts, to chemical processes and the like.

,The objectofthe invention is the provision of an improved'construction of variable stroke pump which will be strong, durable, easily made and fully satisfactory in operation.

The invention consists broadly of a variable stroke pump comprisinga part guided to reciprocate and adapted by its reciprocation to effect the pumping, .a leveradapted. to oscillate about an axis transverse to the direction of reciprocation ofsaid part, a pivotal connection between said lever and said part, having a pivotal axis parallel Figure 2 is an end elevation of the same looking from the left of Figure 1,

Figure 3 is a sectional side scale of the pump proper, I

Figure 3A is a view of a portion of Figure 3 with the parts shown at a different operative position, I s I Figure 4 is an end elevation of another structure according to the invention comprising two pumps and a common driving motor, Figure 5 is a plan of the same, Figure 6 is a side elevation of the same looking fromthe left of Figure 4. l Referring first to Figures 1 to 3, and particue evation to a-larger larly to Figure3, the pump proper comprises a (say vertically) reciprocating plunger I which passes at its lower end through packing 2,held in placeby means of a gland 2a into a pump space la in the well known way. Said plunger l is guided so as to be constrained to reciprocate in a true vertical line. At a point conveniently above the pump space la said plunger is connected to a lever 3, whose axis intersects the axis of said plunger, by a connection which as will be hereinafter more particularly described, permits said lever both to slide along its own axis relative to said plunger and to oscillate relative to said plunger about a horizontal axis which passes through the point of intersection of its own axis and that of said plunger. Said lever 3 at one end (on one side of the plunger axis) is pivoted at. 4 to' a fixed horizontal axis parallelto its axis said fixed. axis l.

. plunger during such reciprocation;

said lever Srelative to said plunger of oscillation relative to the plunger I l, (and, at

its other end (on the otherside of. the plunger axis) is actuated by a crank '53 and connecting rodG so as to oscillate .up anddown about the It will be seen thatby this.

oscillatibnof said lever'3 about said fixed .axis 4 the plunger l is vertically reciprocated'tl'le, lever both oscillating and sliding relativev to j said As willloe hereinafter more particularlyiida fscribed the said, fixed axis 4 aboutwhi'chisaid lever 3 is oscillated is itself capable of being'a'djusted towards and away from the axis of said plunger l, said lever sliding longitudinally of its own axis relative to said plunger to accommodate such adjustment. At one limit of 'suc'h adjust ment said fixed axis i intersects .the plungenaxis,

as shown in Figure ZA and the amplitude of,.re-'

ciprocation of'the plunger l is reduced to zero. at the other limit, said fiXed axis 4 is relatively remote from said plunger axis, and the point of connection 1 of the lever 3 to the connectinglrod ii is relatively'close tosaid plunger axis. The amplitude of v reciprocation of said plunger i is therefore a maximum.v By adjusting said fixed axis 4 to intermediate positions betweensaid two limits the-amplitude of oscillation of the plunger 1 will have. intermediate values between zero and the said maximum.- v v a More particularly, the aforesaid connection of said plunger. l and said lever 3 is effected by mounting on the upper endof said plungera cross head 8 in the form ,of a massive rectangular frame. A-cylindrical trunnion fi lbridges thetwo opposite upright frame members of said cross head 8 with its ends rotatable "insaid upright members, and said trunnion has a central transverse hole through it through which s'aidlever 3 passes.- This hole and said lever 3 are of circular section as shown in Figure 2. It will beseenthat the axis of said trunnion 9 constitutes the axis about which said lever -3 reciprocates relativeto said plunger I andthat at the same'time said hole in said-trunnion permits of the sliding of longitudinally of its oWn axis.

A tail rod N3 is rigidly attached to; and extends .upwards from, the top ofsaidcross head 8, and

said tail rod passes through a fixed guide bearin ll so as to maintain the plunger -l, inits true vertical axis as aforesaid. 1f:

In the particular construction being described the adjustable fixed axis d about which said lever 3 oscillates is'constituted by pivoting the end of said lever to the extremity of anarml2 projecting rigidly from a-sector l3 whose arcuate periphery has worm wheel threads. Hi which are in engagement with a worm E5 on a manually operated adjusting spindle H3.- The. oscillation axis ll of this sector I3 is parallel tothe axis of direction, the end of said arm moves away from said trunnion, pulling the lever through said hole. Said arm I2 is so shaped and arranged that when the sector I3 is rotated to the limit in the first named direction, said arm is in line with said lever 3 and extends into the hole in the trunnion 9 to the point at which the said adjustable fixed axis 4 intersects the axis of said trunnion. This is the position of zero reciprocation of the plunger I and is illustrated in Figure 3A. I

A clamp I8 is provided for locking the secto I3 at any position to which it is adjusted, so that the forces applied to said sector when the pump is reciprocated are not taken by the worm I and worm wheel threads I4.

The construction above described enables the stroke adjustment of the pump to be eifected by means of parts of simple construction and ample bearing surfaces. The continuously rotating crank 5 is mounted on the output shaft I9 of a geared motor 20.

provided in said conduit 22 to ensure that fluid flow between the said intermediate point and the two end can only flow in the appropriate direction. I

Describing now certain constructional details,

7 the pump space I a and port 22 are formed in a relatively massive block 25. Upon this block is mounted a frame structure which carries the upper bearing II for the tail rod I0, and also the worm I5 and the sector I3 and associated parts. This frame structure comprises an integral piece consisting of a bottom 26, which is mounted flush on the top of the block 25, and two side walls 21 and 28 upstanding vertically from said bottom 26. On the top of these side walls 21 and 28 is mounted a top piece 29 which is formed with a boss 30 which carries said bearing I I.

These side walls2'I and 28 towards their upper ends are extended horizontally to the left (according to Figures land 3) and at the left extremities of these extensions they are joined by means of horizontal bars 3I and 32 spaced vertically one above the other. These bars carry the bearings for the spindle Ifi of the worm I5 as clearly shown in Figure 3. Said spindle I6 is manually rotated by means of a knob 33 at its upper end.

formed respectively with bosses 34 and 35 which receive the ends of said pivot pin, and which between them locate said sector I3 axially.

Said sector has an arcuate slot 36 through it, and the aforesaid clamp I8 is constituted by a collar fast on a rod 31 which passes through said slot 36 and screws into a block 38 formed integrally on the inner surface of the wall 21. The

' wall 28 is, as shown, cut away to make room for said rod 31 and also to give easier access to said sector I3 and worm I5, said rod 31 is provided with a hand knob 39.

It will be seen that, when the rod 31 is screwed 4 tightly into the block 38, said sector I3 will be clamped tightly between said block 38 and the collar IB. When said rod 31 is slightly unscrewed the sector I3 can be freely actuated by means of theworm I5.

The block 25 is mounted on a pedestal element 40 which in turn is mounted on a base M, and the geared motor is mounted on a bracket 42 which is also mounted on said base 4|. It might, however, be preferred to mount the motor bracket direct on the pump structure somewhat in the same way as in the dual system described below.

Referring now to Figures 4, 5, and 6, these figures illustrate the application of the invention to an arrangement in which two pumps are driven by a common motor. In this arrangement'there are two pump structures each of which is identical with the structure illustrated in Figure 3, except that in one of said structures the walls 2'! and 28' are right and left instead of left and right. The same references have been applied to Figures 4, 5, and 6 as to Figures 1 2 and 3 to designate the same parts.

These two structures are arranged in spaced relation side by side with their walls 21 facing each other and their axes I'I coincident, and between said structures is mounted a single geared motor 43 whose output shaft is designated by the reference 44. This shaft 44 is, as shown, parallel to the said coincident axes I1 of the two pump structures and, at its two ends said shaft 44 has cranks 45 mounted on it which are connected, by means of connecting rods 46 to the respective levers 3 at their points I. Thus the motor drives both pumps.

The two pump structures are mounted on respective pedestal elements 4'! which in turn are mounted on a common bar member 48.

The geared motor 43 is mounted on a bracket 49 which in this case is overhead and is secured 'to a horizontal overhead bridging member 50 which extends between the two walls 21 of the pump structures. As will be clear from the drawing this bridging member 50 is formed with two downwardly depending lugs 5| which are secured flush to the respective walls 21 of the pump structures.

The reference 52 designates additional strengthening elements by which the geared motor is secured to the two pump structures.

It will be appreciated that, in the arrangement of Figures 4, 5 and 6, each pump remains independently adjustable by the manipulation of its adjusting knob 33 and its clamping knob 39.

It will be readily understoodthat the number of pumps which could be driven by a common motor is not limited to two. A multiple pump unit may obviously be constructed by utilisingmerit guided to reciprocate in a straight line, and

adapted by its reciprocation to effect the pumping, a fixed part, a lever, a pivotal connection connecting said lever to said fixed part, means for oscillating said lever about said pivotal conmotion, a trunnion rotatably mounted on said element, the said trunnion being formed with a hole therethrough, said lever slidably extending through said trunnion hole, whereby oscillation of said lever effects reciprocation of said element, and means for adjusting said fixed part for sliding said lever longitudinally in said hole, thereby varyingthe stroke of said element, said adjusting means being operable to bring said pivotal connection into said trunnion hole, thereby adjusting the stroke of said element to zero.

2. A variable stroke pump comprising a plunger element and having one end in a pump space, means guiding said plunger element to reciprocate a cross head rig-idly secured to the other end of said plunger element, a tail rod rigidly secured at one end to said cross head and extending from said cross head coaxially with, and in a direction away from, said plunger element, means guiding said tail rod to reciprocate, a, trunnion rotatably mounted in said cross head, a fixed part, a lever, a pivotal connection connecting said lever to said fixed part, means for oscillating said lever about said pivotal connection, said lever passing slidably through a hole in said trunnion, whereby oscillation of said lever efiects reciprocation of said plunger element, and means for adjusting said fixed part for sliding said lever longitudinally in said hole and thereby varying the stroke of said plunger element, said adjusting means being operable to bring said pivotal connection into said trunnion hole, thereby adjusting the stroke of said element to zero.

3. A variable stroke pump comprising an element guided to reciprocate in a straight line and adapted by its reciprocation to effect the pumping, a rotatable sector having Worm teeth on its arcuate surface, a rotatable worm in mesh with said worm teeth, an arm extending rig-idly from said sector, a lever, a pivotal connection conmeeting an end of said lever to the end of said arm, means for oscillating said lever about said through a hole in said trunnion, whereby oscillation of said lever efiects reciprocation of said element, rotation of said sector by said worm causing said lever to slide in said hole in said trunnion and thereby vary the stroke of said element, said sector having a position at which the end of said arm extends into said hole in said trunnion thereby adjusting said stroke to zero.

4. A variable stroke pump comprising an element guided to reciprocate in a straight line and adapted, by its reciprocation to efiect the pumping, a rotatable sector having worm teeth on its arcuate surface, a rotatable worm in mesh with said Worm teeth, a lever, a pivotal connection connecting said lever to said sector, means for oscillating said lever about said pivotal connec-' tion, and a second pivotal connection connecting said lever to said element, said second pivotal connection permitting said lever to slide longitudinally of itself relative to said second pivotal connection, whereby oscillation of said lever effects reciprocation of said element, and rotation of said sector by said worm causes variation of the stroke of said element.

GILES PHILIP ELIOT HOWARD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 273,276 Hawkinson Mar. 6, 1883 1,171,787 Harris Feb. 15, 1916 1,292,457 Hall Jan. 28, 1919 1,937,803 Bagby Dec. 5, 1933 2,147,989 Puurmann Feb. 21, 1939 2,259,713 Valentine Oct. 21, 1941 FOREIGN PATENTS Number Country Date 498,078 Great Britain 1939 

